Method of making meat curing salt
compositions



United States Patent Ofice Re. 26,561 Reissued Apr. 15, 1969 26,561METHOD OF MAKING MEAT CURING SALT COMPOSITIONS Arthur E. Poarch, MillValley, Calif., and Michael W.

Kossoy, Decatur, Ill., assignors to Western Dairy Products, Inc., SanFrancisco, Calif., a corporation of California No Drawing. Original No.3,275,459, dated Sept. 27, 1966,

Ser. No. 344,234, Feb. 12, 1964, which is a continuationin-part ofapplication Ser. No. 29,585, May 17, 1960. Application for reissue Sept.27, 1967, Ser. No. 675,257

Int. Cl. A23!) 1/01; A23! 3/34 US. Cl. 99-222 7 Claims Matter enclosedin heavy brackets appears in the original patent but forms no part ofthis reissue specification; matter printed in italics indicates theadditions made by reissue.

ABSTRACT OF THE DISCLOSURE A method for making a curing saltcomposition, suitable for the curing of meat and meat products,characterized by homogeneity of mixture, and formed of a major portionof sodium chloride and a minor portion of a curing salt, said methodcomprising forming a solution by dissolving the minor portion in anamount of water sufiicient to fully wet but not suflicient to fullydissolve said major portion, admixing the solution with said majorportion of sodium chloride and thereby forming a homogeneous paste, andheating said paste to drive off water therefrom and form a substantiallydry, homogeneous mixture of sodium chloride and curing salt.

This application for Letters Patent is a continuation-inpart ofco-pending application Ser. No. 29,585, filed May 17, 1960, nowabandoned.

This invention relates to the curing of meats and meat products, andmore particularly to meat curing compositions and to a process of makingthe same.

The use of sodium nitrite and/or sodium nitrate to cure meats and meatproducts is a well-known and standard practice of the meat industry.These chemicals provide compounds which react with the hemoglobin ofblood to provide a stable red color in the processed meat.

In commercial practice, sodium nitrite and sodium nitrate (or thepotassium salts of nitrite and nitrate) are mixed with sodium chloridein order that the bulk of the mixture can be easily used by theprocessor. The ratios of sodium nitrite, sodium nitrate and sodiumchloride may i be varied depending upon the degree of curing desired andthe amount of salt that is to be added to the end product. By way ofillustration, 100 pounds of curing salt mixture may consist of sixpounds of sodium nitrite, 4 pounds of sodium nitrate, and 90 pounds ofsodium chloride.

If sodium nitrite, sodium nitrate and sodium chloride, each in granularor pulverized form, are compounded by mechanical mixing, there is noassurance that the amount of nitrite from a portion of the mixture inthe top of the container will be the same as the nitrite concentrationin the product from the bottom of the container, it being well-knownthat crystalline or pulverized chemicals of different types often cannotbe mechanically mixed to result in an absolutely homogenous product.

Also, the transportation of mechanically mixed curing salt products fromthe point of preparation to the place of use often entails aconsiderable amount of shaking and vibration. This aggravates theproblem by increasing the rate of sifting action to result in theconcentration of one or more of the components of the product at eitherthe top or the bottom of. the shipping container. The degree Qil ofsitting is not predictable, being dependent upon the particle sizes ofthe various constituents, their relative densities, the amount and typeof vibrational forces, and the container configuration.

In the meat industry it is not usual for the processor to use curingsalts in single container increments. It is the usual practice for theprocessor to remove, say, 5 to 10 pounds of curing salt from a largecontainer of curing salt product for the preparation of a single lot ofpumping pickle or as a direct additive to a batch of comminuted meat,such as sausage. If the product has shifted, the first increment removedfrom the container will be different in composition from the lastportion removed, and hence the meat processor may either undercure hismeat product or add nitrite and/or nitrate in excess of the legal limit(200 parts of nitrite (N0 per million parts of final processed meatproduct). Either situation can result in a considerable loss of productto the meat processor.

The prior art has suggested ways of overcoming the separation problem ina curing salt mixture. This prior art comprises US. Patents 2,054,623and 2,054,624. The solutions therein proposed to this separation problemare on the one hand, a complete fusing of the mass of sodium nitrite,sodium nitrate and sodium chloride, and, on the other hand, a fusing ofthe nitrites or nitrates into the physical structure of the saltcrystals or globules. In fusing the nitrites or nitrates into thephysical structure of the salt crystals, a water solution of sodiumchloride and the sodium or potassium salts of nitrous or nitric acids,or both, is flash dried on the surface of a heated drum, removed fromthe drum by a knife blade, cooled, and packaged. The process takesadvantage of the lower melting point of a eutectic mixture of the saltsand the true melting point of the pure salts alone.

In connection with this prior art proposal, it has been observed byselected staining and microscopic examination of the end product thatnot all of the nitrite and nitrate is trapped within the salt crystals.An appreciable amount of free nitrite and nitrate is present, and it isap parent that there likewise exists a percentage of pure salt crystalsthat contain no nitrite or nitrate. Closer study of this prior artprocess and product reveals that each crystal of salt does notnecessarily contain sodium nitrate and/or nitrite in the same proportionas is present in the original water solution of the 3 salts involved. Infact, the final product consists of free salt, free sodium nitrate, freesodium nitrite, and a heterogeneous mixture of fusing productcombinations, of 2 or more of the salts present in the original watersolution. It follows that this known prior art process is only a partialanswer to the problem of preventing the separation of the components ofthe cure salt formulation. It is still possible for one or more of theconstituents to be mechanically separated from the body of the cure saltby vibration or handling of the final package. This drum fusion processis, however, an improvement over a mechanically mixed cure salt.

The process of flash drying a water solution of the curing salts is arather expensive method. Sodium chloride is soluble up to a maximum ofabout 40 parts in parts of hot water (2:5); sodium nitrite is soluble inthe amount of about 163 parts in 100 parts of hot water; and sodiumnitrate is soluble to the extent of about parts in 100 parts of hotwater. It may be seen that the amount of sodium chloride in the curingsalt is the limiting factor in reaching the maximum solids content ofthe solution of salt to be drum dried.

The essential object of the present invention is to provide a method ofproducing a curing salt mixture, the end product of which method isnovel and consists of an intimate, non-separating mixture of fusednitrate, nitrite and sodium chloride.

A further object of the present invention is to provide a curing saltmixture production method which is more economical to practice than thedrum or flash methods above described.

Other objects and advantages of the invention will be apparent from thefollowing description constituting the specification of the invention.

In accordance with the method of the present invention, a water solutionis formed by dissolving 6 grams of sodium nitrite and 4 grams of sodiumnitrate in 30 grams of water, the water being at about room temperature.The resulting solution is added to 90 grams of sodium chloride which hasbeen pulverized to substantially pass through a 325 mesh sieve. Thecombined materials are then mixed together so as to completely wet thesodium chloride with the nitrate and nitrite solution and to form aheavy paste of almost dough-like consistency. The paste is then evenlyspread on the surface of a metal sheet to form a layer of about /2 inthickness. The metal sheet bearing the salt paste is then placed in aheater atmosphere of about 330 F. and allowed to remain in thisatmosphere until the entire salt mass reaches 330 F. The dried salt massis then removed from the heated atmosphere, cooled to about 200 F., andcrushed to the desired particle size.

The process may be practiced on either a batch basis or a continuousproduction basis.

The specific proportions given in the above example are not to beconsidered limiting, as the constituents may be combined in any relativeproportion in which they provide a usable curing salt mixture. Also, thegiven particle size for the sodium chloride is not to be consideredlimiting. Any particle size may be selected. It is desirable, however,that the particles be relatively small and that they be fairly uniformlysized.

The amount of water employed should be at least sufficient to entirelywet the sodium chloride but less than that required to fully dissolvethe sodium chloride, with the minimal amount of water being preferredbecause of the lesser expense involved in driving it off. 30 parts ofwater is the least amount of water which can be used to fully wet 90parts of sodium chloride. The ratio here varies somewhat with theparticle size of the salt. For instance, if 200 mesh sodium chloridewere used, only 25 parts of water would be required to insure completewetting of 90 parts of the sodium chloride.

The 330 F. temperature given in the foregoing example is the eutecticreaction isotherm for [a] the given mixture of sodium nitrite, sodiumnitrate and sodium chloride. The important point here is that whatevermixture is selected for the end product, the wetted sodium chloride isto be heated until it attains [this] the eutectic reaction isotherm themixture selected.

The wetted sodium chloride should be maintained relatively quiescentuntil it has reached the fusing temperature.

Upon microscopic examination of the cooled, crushed salt mixture, andthrough the use of selective staining methods to distinguish betweensodium nitrite, sodium nitrate and sodium chloride, an unusual and novelproduct is apparent. The surfaces of the sodium chloride crystals arerandomly covered by a plurality of small sodium nitrite-nitrateparticles fused thereon. In some instances, two or more salt crystalsare joined by small fused particles of the nitrite-nitrate bodies. In noinstances of examination have there been observed what are described inthe aforementioned prior art patents as heart-shaped nitritenitrateinteriors of a larger sodium chloride crystal or particle.

The following is believed to be an accurate explanation of what takesplace during the process to provide the end product described:

As previously stated, the amount of water employed to make the paste issutficient to completely dissolve the sodium nitrite and sodium nitratebut quite insufficient to completely dissolve the sodium chloride.During the wetting of the latter, each undissolved salt particle iscompletely surrounded by a film of water in which is dissolved sodiumchloride, sodium nitrite and sodium nitrate. When sodium chloride of arelatively narrow range particle size is used, each salt particle willhave associated with it a given quantity of sodium nitrite and sodiumnitrate in water solution.

When the paste is heated, the water progressively evapcrates, and thesodium chloride that was dissolved from the salt particle surfacesduring the step of preparing the paste recrystallizes onto the surfaceof the undissolved salt present. Further and final evaporation of thewater causes the sodium nitrite and sodium nitrate to crystallize andcause the resulting crystals to be deposited on the surface of each ofthe sodium chloride particles.

Continued heating of the mass to a temperature above the eutecticreaction isotherm of sodium chloride and sodium nitrite or of sodiumchloride and sodium nitrate causes the contacting surfaces of the sodiumchloride and the nitrate or nitrite (both, if both are present) to melt.As the temperature is then decreased below the eutectic reactionisotherm, the eutectic composition which is present solidifies and actsas a cement to hold the nitrite or nitrate particles to the sodiumchloride crystals.

The eutectic cement bond between the sodium chloride and the nitrate ornitrite particles appears to be quite strong. Careful crushing of thebonded mass of the cured salt mixture does not result in the dislodgmentof any appreciable quantity of nitrate or nitrite particles from thesodium chloride crystal surfaces.

Since substantially all of the nitrite and nitrate particles are bondedto sodium chloride crystals in a ratio which is approximately that ofthe original mixture, no separation can occur. In other words, anyaliquot portions of a quantity of this cure salt mixture will have aconsistent chemical analysis. It is therefore possible to provide a meatprocessor with a cure salt mixture that contains the same amounts ofnitrite and nitrate for each pound of product used at all times.Furthermore, there is no sifting or segregation of one or more of thecure salt components when the commercial, packaged product is vibratedduring transit.

The economies offered by the subject method in comparison with the priorart methods earlier described are apparent from a mere comparison of thewater removal problem involved. In the present case the production ofparts of finished curing salt mixture requires that only 30 parts ofwater be evaporated. When the drum flash crystallization method is used,at least 250 parts of water must be evaporated for each 100 parts ofcure salt produced.

It is of course to be understood that potassium nitrite and potassiumnitrate may be employed in place of sodium nitrite and sodium nitrate.One or the other of nitrite and nitrate salts may be employed incombination with sodium chloride, or a combination of nitrite andnitrate salts may be employed with sodium chloride. Whatever thecombination and identity of curing salt constituents, the wetted sodiumchloride is to be heated to the eutectic reatcion isotherm of themixture of salts selected.

What is claimed is:

1. A method for making a curing salt composition for the curing of meatand meat products comprising fully dissolving in a predetermined amountof water an amount of salt selected from the group of salts consistingof the nitrite and nitrate salts of sodium and potassium, homogeneouslymixing the resulting solution with substantially uniformly sized sodiumchloride particles, said resulting solution being present in an amountsufiicient to fully wet the sodium chloride but insufficient to fullydissolve said sodium chloride, thereby forming a homogeneous paste,raising the temperature of the mixture to its eutectic reactionisotherm, and cooling said mixture to a temperature below said eutecticreaction isotherm.

2. The method of claim 1 including cooling said mixture to about 200 F.and crushing said cooled mixture to a particle size condition.

3. A method for making a curing salt composition for the curing of meatand meat products comprising dissolving in 30 parts by weight of water 6parts by weight of sodium nitrite and 4 parts by weight of sodiumnitrate, homogeneously mixing the resulting solution with 90 parts byweight of sodium chloride particles to form a homogeneous paste, raisingthe temperature of said mix ture to about 330 F., and cooling saidmixture to a temperature below 330 F.

4. The method of claim 3, said mixture being cooled to about 200 F., andsaid mixture being thereafter crushed to a particle size condition.

5. A method for making a curing salt composition for the curing of meatand meat products comprising fully dissolving in water a salt selectedfrom the groups of salts consisting of the nitrite and nitrate salts ofsodium and potassium, mixing the resulting solution with sodium chlorideparticles to form a homogeneous mixture, the parts by weight ratio ofthe solvent or water phase ot said resulting solution to said sodiumchloride being within the range of about 1:3 to less than 5:2, saidhomogeneous mixture thereby being a paste, heating said mixture to driveoff the water and to raise the temperature of the resulting residue tothe eutectic reaction isotherm of the salts constituting said residue,and cooling said residue to a temperature below said eutectic reactionisotherm.

6. The method of claim 5 including cooling said residue to about 200 F".and crushing the cooled residue to a particle size condition.

7. A method for making a curing salt composition for llie curing of mm:and meat products comprising fully dissolving in a predetermined amountof water an amount of salt selected from the group of salts consistingof (he nitrite and nitrate salts of sodium and potassium, homogeneouslymixing the resulting solution with substantially uniformly sized sodiumclilorirlc particles, said resulting solution being present in an amountsufl'icicnt to fully we! the sodium chloride but insufficient to fullydissolve saizl sodium chloride, thereby forming a homogeneous paste, andheating said paste to drive of] the writer and form a homogeneousmixture of sodium chloride and selected salt.

References Cited The following references, cited by the Examiner, are olrecord in the patented file of this patent or the original patent.

UNITED STATES PATENTS 2,054,625 9/1936 Grifiilh 99-222 LIONEL M.SHAPIRO, Primary Examiner.

U.S. Cl. X.R. 99159

